从 0,0 开始捕获屏幕截图

Question

我正在使用以下代码进行屏幕截图

UIGraphicsBeginImageContext(self.view.frame.size);

blendMode:kCGBlendModeClear alpha:1.0];

[self.view.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);

return viewImage;

它工作正常，但它返回全屏，我想要一个特定框架的屏幕截图，比如( 100,100,200,200)，我尝试在以下方面进行更改：

UIGraphicsBeginImageContext(self.view.frame.size);

但没有成功。

Answer 1

试试这个：

float x = 100;
float y = 100;
CGSize size = CGSizeMake(200,200);

UIGraphicsBeginImageContext(size);
CGContextRef c = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(c, -x, -y);
[view.layer renderInContext:c];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Answer 2

只需使用三行代码。

    UIGraphicsBeginImageContext(CGSizeMake(320, 480));
    [self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *frame= UIGraphicsGetImageFromCurrentImageContext();